The Supreme Court ruled in the case of Freddie Lee Hall, on Florida's death row for more than three decades. / AP

by Richard Wolf, USA TODAY

by Richard Wolf, USA TODAY

WASHINGTON - The Supreme Court made it more difficult Tuesday for states to execute prisoners who claim an intellectual disability, marking the first time it has fine-tuned its landmark 2002 decision barring the death penalty for those with mental impairments.

The court ruled that Florida must apply a margin of error to IQ tests administered to Freddie Lee Hall, 68, who killed a 21-year-old pregnant woman and a deputy sheriff in 1978. The state had argued that any test score above 70 made prisoners eligible for a death sentence, despite medical guidelines that permit scores to reach 75.

"Intellectual disability is a condition, not a number," Justice Anthony Kennedy said in the 5-4 ruling, joined by the court's four liberal justices.

The decision will affect a handful of states with similar policies among the 32 states with death penalties on the books. Though very few prisoners with intellectual disabilities will be granted reprieves as a result, the ruling clarifies a delicate area of criminal law.

It comes as states' capital punishment procedures are under siege, beset by a shortage of drugs needed to perform lethal injections and rejuvenated efforts by disability rights groups to stop executions of prisoners with mental impairments. A federal appeals court blocked Texas this month from executing a death row prisoner claiming intellectual disability.

"Florida's law contravenes our nation's commitment to dignity and its duty to teach human decency as the mark of a civilized world," Kennedy said. "The states are laboratories for experimentation, but those experiments may not deny the basic dignity the Constitution protects."

Justice Samuel Alito and the court's three other conservatives dissented, arguing that the court should not strike down a state law and interpret the Eighth Amendment based on "the evolving standards of professional societies" such as the American Psychiatric Association.

The case marked a return for the court to Atkins v. Virginia, its 2002 decision that executing people with intellectual disabilities violates their Eighth Amendment rights against cruel and unusual punishment.

"The Supreme Court reaffirmed its commitment to ensuring justice for individuals with intellectual disability," said Peter Berns, CEO of The Arc, which advocates on behalf of people with developmental disabilities. "Disability advocates and legal experts across the country will look back to this decision for years to come."

The key dispute ever since Atkins was decided has been who gets to define "mental retardation," now referred to as intellectual disability - states or medical professionals. The Supreme Court set a three-prong test that includes intellectual functioning, adaptive behavior and age of onset. Florida doesn't consider the latter two prongs if the IQ score is above 70.

At most, nine states employ a strict IQ score cutoff of 70, Kennedy noted, but in four of those, state courts have not upheld the laws. That leaves only Alabama, Arizona, Kentucky and Virginia in the same category as Florida; none of those states has executed anyone this year, nor do they have any executions scheduled.

No one in Hall's precise situation has been executed in the 12 years since the high court prohibited the death penalty for people with intellectual disabilities. Four other death row residents in Florida and Alabama face similar predicaments.

The court's ruling could have broad repercussions by spelling out exactly what the justices meant when they prohibited executing people with intellectual disabilities without defining specifically who is and who isn't disabled.

"Consistent with universal statistical principles and clinical practice, Florida must now take the standard error of measurement into account in determining whether a defendant satisfies the clinical definition of intellectual disability and is thus protected from execution," said Hall's attorney, Eric Pinkard.

The number of executions in the USA peaked at 98 in 1999, then dropped to 39 by last year, according to the Death Penalty Information Center. Twenty prisoners have been executed this year.

From 1984 to 2001, 44 people with intellectual disabilities were executed. Since the Atkins ruling, several hundred claims involving such impairments have been filed by prisoners on death row, representing about 7% of all cases, according to John Blume, a Cornell University law professor. Slightly more than 100 sentences have been reduced as a result, a 28% success rate.